54 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 2 



NOTES ON EMPOASCA MALI LE B. 



By F. L. Washburn, St. Anthony I'ark, Minn. 



The following observations resulting- from two years' work with 

 the above named insect, illustrate, it is believed, some hitherto un- 

 known facts in connection with its life history. These points are best 

 discussed under separate headings, namely: 1. The Fall-Laid Egg; 

 2. Oviposition during the Summer Months; 3. Food Plants; 4. Dif- 

 ferent Stages and Number of Broods; 5. Economic Suggestions. 



1. The Fall-Laid Egg: The finding of egg blisters on young ap- 

 ple trees in 1907 was reported before this Association at the last an- 

 nual meeting, and pictures of the blisters exhibited. That paper, 

 with illustrations, was published in Vol. 1, No. 2. of the JourNx^l op 

 Economic Entomology. The blisters shown in that article measured 

 about .75 mm. long by .4 mm. broad, and the fact that Empoasca 

 was reared from them authorizes the statement that they belonged to 

 this species. These blisters were found upon the apple. Certain egg 

 blisters on the small branches of the elm, similarly located with re- 

 spect to the new growth of the elm, were found this year by Doctor 

 Franklin, and they appear to be the same as the blisters found upon 

 the apple. We were able to discover no difference between these and 

 the apple blisters, the measurements were the same, and they were 

 the same in general appearance. The contained eggs were like those 

 contained in the blisters on the apple. It seems possible that these 

 are also blisters of E. mali, or perhaps some very closely allied form. 

 The fact that the elm and the apple are not closely related may not 

 be taken as evidence against this, for it is quite possible that the char- 

 acter of the bark which the tree bears on its small branches may have 

 a more important bearing upon this matter than does the relationship 

 of the species. The egg contained in the blister upon the apple is 

 about as long as the blister itself, hyaline and semi-opaque. It is 

 covered by the epidermis and the corky portion of the bark, and only 

 a thin layer of cortical parenchyma. The eggs are much narrower 

 than their blister-like envelope, measuring only .2 mm. in their great- 

 est width. In cross section they are nearly circular, slightly curved 

 from .end to end, and round at the points. Further, they are of about 



Explanation of Plate 2: Figs. 1, 2, 3, 4 aud 5 represent five successive 

 stages of the nymph; Fig. 6, the adult leaf hopper; Fig. 7, the newly hatched 

 nymph (summer) issuing from petiole of clover. The central figvu'e illus- 

 trates the appearance of the terminal portion of an apple twig upon which 

 this leaf hopper is working. (Reprint from 12th Rept., State Ent., Minn. 

 1908.) 



